Improving electric submersible pumps efficiency and mean time between failure using permanent magnet motor

Abstract

• This research performs a critical review of the application of PMMs in ESP artificial lift. • The research presents different field case histories that have utilized ESP-PMM and shows the main advantages and limitations of this assembly. • Based on the data collected from these field applications, an application criteria for the ESP-PMM system was developed. • Many field applications have reported significant improvements in the ESP life and performance when coupled with PMMs. • Some of the major problems associated with harsh downhole conditions can be easily overcome by accounting for these problems and using proper designs and operating conditions to avoid degradation of the PMM and early failure of the ESP. Electrical submersible pumps (ESP) are one of the most utilized artificial lift methods to increase oil recovery. Conventional ESPs operate using an asynchronous three phase induction motor. Although this type of motor has proven to be effective in powering the ESP, it has several disadvantages and is prone to failure especially in severe downhole conditions. This research investigates the replacement of the conventional asynchronous three phase induction motor with a synchronous two-to-four pole permanent magnetic motor (PMM) for a prolonged ESP mean time between failure and a higher output with lower energy requirements. PMMs have been applied in multiple fields worldwide when using ESP with different string designs and operating conditions. The advantages of using PMMs with ESP have varied significantly depending on the wellbore properties including depth, temperature, and pressure; reservoir rock properties including unconsolidated formations; and reservoir fluid properties including the presence of wax, asphaltene, carbon dioxide, hydrogen sulfide, and high total dissolved salts. Since the performance of the PMM with ESP varies from one reservoir and formation to another, it is important to set a guideline to the application of ESP-PMM based on the aforementioned properties. This research therefore provides proper screening criteria for the application of PMM with ESP based on wellbore, formation rock, and reservoir fluid properties. The screening criteria are constructed based on a comprehensive database of real field implementations of PMM with ESP in more than 10 different countries worldwide.